A new study shows that equatorial Pacific ocean currents, driven by stronger winds, have accelerated over the past 30 years, with consequences for global climate and El Niño patterns. The findings, based on data supported by the National Oceanic and Atmospheric Administration, may improve the accuracy of climate models and the ability to predict the El Niño/Southern Oscillation.


The dynamic changes of the El Niño-Southern Oscillation (ENSO) are inseparable from an important ocean layer. Journal of Geophysical Research: A new study published in Oceans reports that the upper ocean circulation in the equatorial Pacific has accelerated significantly over the past three decades.

The main driver of this acceleration is an increase in atmospheric winds, which results in stronger, shallower ocean currents. These changes may affect regional and global climate patterns, possibly affecting the frequency and intensity of El Niño and La Niña events. This study explores these long-term trends from a spatial perspective based on observational data, extending at least another decade from previous studies.

Trends in west-east near surface ocean currents from 1993 to 2022. Blue indicates an increase in westward current; red indicates an increase in eastward current. The largest trend occurs in the central tropical Pacific (black box). Velocity data from three equatorially moored buoys (Yellow Diamond) provide a subsurface view of long-term trends in upper ocean velocity. Source: Chart: FranzPhilipTuchen Satellite Imagery Background NOAANESDIS

The research team, led by Franz Philip Tuchen, a postdoctoral scientist at the NOAA Cooperative Institute for Marine and Atmospheric Studies (CIMAS) at the University of Miami's Rosenstiel School, in collaboration with NOAA's Atlantic Oceanographic and Meteorological Laboratory (AOML), synthesized three decades of long-term ocean and atmospheric observations from satellites, moored buoys, and ocean surface drifters.

By integrating reanalysis of wind data and satellite altimetry data into a high-resolution, gridded time series of near-surface ocean currents, this study provides a new and comprehensive view of upper-level Pacific current changes to date.

The results show that stronger winds in the equatorial Pacific significantly accelerate the westward near-surface ocean currents in the central equatorial Pacific by about 20%. Poleward ocean currents north and south of the equator also accelerated, increasing by 60% and 20% respectively.

"The equatorial temperature line - a key ocean layer for El Niño-Southern Oscillation (ENSO) dynamics - has steepened significantly," Tuchen said. "This steepening trend may reduce the amplitude of the Eastern Pacific El Niño/Southern Oscillation and favor more frequent central Pacific El Niño events, potentially altering regional and global climate patterns associated with El Niño/Southern Oscillation."

The researchers note that this study provides a baseline for climate models, which have limited success in accurately representing Pacific circulation and sea surface temperature trends. The findings could help improve the predictability of El Niño/Southern Oscillation events and associated weather patterns, particularly for regions like the United States, where changes caused by El Niño/Southern Oscillation can bring significant climate variability.

Compiled from /ScitechDaily

DOI:10.1029/2024JC021343